Fix the issue with file open/save/folder selection and other comctl dialogs ending up behind the browser window on desktop
Windows AURA with glass.

This started occurring because of the recent change to use native tooltips on Windows AURA. It looks like the activation code
in Windows gets confused because of the tooltip windows having the WS_EX_TOPMOST style. Removed this style from the tooltip
window. The old tooltip code on non AURA was not topmost as well.

Fixes bug https://code.google.com/p/chromium/issues/detail?id=306572

R=sky@chromium.org, sky

Review URL: https://codereview.chromium.org/27551006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229194 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229194